Lofthouse Cookies

In a large bowl, whisk together flour, cornstarch, baking powder, and salt.  In another large bowl using a hand mixer, beat butter, cream cheese, and sugar together until light and fluffy. Add egg and extracts and beat until well combined. Add dry ingredients and beat until just combined. Transfer dough to plastic wrap and smooth into a disc. Dough will still be soft and sticky at this point. Refrigerate until well chilled, at least 1 hour.  Preheat oven to 350° and line 2 large baking sheets with parchment. Lightly flour surface and place dough on counter. Dust top of dough with flour as well. Roll dough out to ½” thick. Use a 3” round cookie cutter to cut cookies and place on prepared baking sheets 2” apart. Gather scraps and re-roll to cut to cut out more cookies.  Bake until edges are just set, but centers are still slightly underdone, 10 to 12 minutes. Cookies shouldn’t gain much color on top. Let cool completely on baking sheets.  Meanwhile, make frosting: In a large bowl using a hand mixer, beat butter until completely smooth and creamy, 2 minutes. Add powdered sugar and beat again until light and fluffy, about 3 minutes more. Add heavy cream, vanilla, and a pinch of salt and beat until combined. Add desired food coloring and beat again to combine.  Use an offset spatula to frost tops of cooled cookies with a thick amount of frosting, then top with sprinkles.